ATDD’s fast response ozone sensor is designed to measure atmospheric ozone. This instrument
uses a chemiluminescent disk in which ozone and coumarin react to produce light. The light
intensity is detected by a photo-multiplier tube and is proportional to the amount of ozone present.
The reaction chamber is made of stainless steel, which has a negligible reaction with ozone.
Since the coumarin dye is depleted by reaction with ozone, the sensitivity of the instrument
decreases with time. Typically a closed-path slow response ozone analyzer is run along side to
allow frequent calibration. A thirty-minute average from both fast and slow instruments will allow a
span calibration correction to be calculated.
Typically the sensor disk is replaced weekly. The sensor disk is secured to a plug in the reaction
chamber by double stick tape. After turning the instrument off, the aluminum plug is simply pulled
out of the reaction chamber for easy sensor disk replacement. Once the new sensor disk and the
plug are back in place the instrument may be turned back on. Open the sensor chamber in
subdued light only and only with the power off otherwise the photo-multiplier tube may be
damaged. Photo-multiplier tubes run ~$500.00.